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An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration to give a conjugated enone. The overall reaction equation is as follows (where the Rs can be H)
In its simplest implementation, base induces conversion of an aldehyde or a ketone to the aldol product. One example involves the aldol condensation of propionaldehyde: 2 CH 3 CH 2 CHO → CH 3 CH 2 CH(OH)CH(CH 3)CHO. Featuring the RCH(OH)CHR'C(O)R" grouping, the product is an aldol. In this case . Such reactions are called aldol aldol ...
3-Pentanone (also known as diethyl ketone) is a simple, symmetrical dialkyl ketone. It is a colorless liquid ketone with an odor like that of acetone . It is soluble in about 25 parts water, but miscible with organic solvents.
It can be considered as a specific variation of the aldol condensation. This reaction is named after two of its pioneering investigators Rainer Ludwig Claisen and J. Gustav Schmidt, who independently published on this topic in 1880 and 1881. [1] [2] [3] An example is the synthesis of dibenzylideneacetone ((1E, 4E)-1,5-diphenylpenta-1,4-dien-3 ...
This reaction is an important approach to the formation of carbon-carbon bonds in organic molecules containing ring systems. As an example, under strong basic conditions (e.g. sodium hydroxide), hexane-2,5-dione (compound A in Figure 1) can cyclize via intramolecular aldol reaction to form the 3-methylcyclopent-2-en-1-one (compound B).
A classic example for favoring the keto form can be seen in the equilibrium between vinyl alcohol and acetaldehyde (K = [enol]/[keto] ≈ 3 × 10 −7). In 1,3-diketones, such as acetylacetone (2,4-pentanedione), the enol form is favored. The acid-catalyzed conversion of an enol to the keto form proceeds by proton transfer from O to carbon.
Dibenzyl ketone, or 1,3-diphenylacetone, is an organic compound composed of two benzyl groups attached to a central carbonyl group. This results in the central carbonyl carbon atom being electrophilic and the two adjacent carbon atoms slightly nucleophilic.
Chiral auxiliaries are incorporated into synthetic routes to control the absolute configuration of stereogenic centers. David A. Evans' synthesis of the macrolide cytovaricin, considered a classic, utilizes oxazolidinone chiral auxiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting the absolute stereochemistry of nine stereocenters.